Retraction Statement: Paper by Qian Y, Ma J, Guo X, Sun J, Yu Y, CaoB, Zhang L, Ding X, Huang J, Shao JF, entitled ‘Curcumin Enhances the Radiosensitivity ofU87 Cells by Inducing DUSP-2 Up-Regulation‘ Cell Physiol Biochem 2015;35(4):1381-93.doi: 10.1159/000373959